External Tooth Lock Washer, For Screw Size 3/8 in Steel, Zinc Plated Finish, 50 PK

External tooth lock washers feature teeth that help to prevent loosening of a nut or bolt by digging into the surface. For maximum holding power, use one between the surface and the bolt head, and use another one between the surface and the nut. The bolt head should be at least the same size as the total diameter of the lock washer. Lock washers are great for use in cases where the bolt may be subject to vibration. •Size: 3/8 inch •Features teeth that extend outward •Prevents loosening of bolt or nut by biting into surface when nut is tightened down •Best to use bolts with large heads to ensure teeth make full contact •Can be used on screws and bolts